Carbon monoxide alarm

[Thingsthatgo]

Last night our carbon monoxide alarm started beeping. I went down to check it and it was indicating 'ventilation' rather than a full alarm. So I opened some windows and it stopped.
But, I'm concerned about what set it off. The boiler wasn't running, but was on a pilot light, that was running fine (not stuttering or orange in colour). We have just had it serviced about a month ago.
We have been doing some DIY - could strong paint fumes set it off?

Get your boiler re checked by whoever serviced it and get another alarm, yours could be faulty?

Normal low VoC interior paint shouldn't set off an alarm but worth monitoring.

I ve just been painting right next to ours, with both oil based primer and water based satin paints, no issues.

I'd get a new alarm and see it if happens again, but I'd also ask the person who serviced the boiler for advice.

We had something like that a couple of years ago. We got another alarm, which was fine and disposed of old one. Have since had it serviced and levels checked - it's fine.

If you can, I'd go out first thing and get another alarm to double check. If that's fine, probably a fault with old alarm. Obviously do bear in mind, that if you're leaving animals in your home while you get this assessed, it's going to affect them a lot quicker, so either take with you, shut outside or leave every possible window open or on catch.

Ours did this and it turned out to be a small gas leak. I’d get it checked to be on the safe side.

Possibly stupid question. Person who serviced it didn’t leave the test cap off, and you have only just closed all your windows which has set it off?

@KievLoverTwo Good thought, but we've had our windows shut ever since. I guess maybe the dust from diy might have got into it. I've popped it outside, but it is still saying ventilate!
We have another alarm, but it doesn't have the sensitivity of this one. I've ordered a new one fromAmazon which should arrive today, so we shall see!
The dog seems perfectly fine.
Thank you for all of your help - I didn't get much sleep last night!